Phosphor powder, light-emitting device, image display device, and illumination device

Abstract

A phosphor powder including phosphor particles of a phosphor represented by a general formula M x (Si, Al) 2 (N, O) 3±y and in which a part of M is substituted with a Ce element, the phosphor powder includes phosphor particles in which a Si/AI atomic ratio is equal to or more than 1.5 and equal to or less than 6, an O/N atomic ratio is equal to or more than 0 and equal to or less than 0.1, 5 to 50 mol % of M is Li, and 0.5 to 10 mol % of M is Ce. In a case where a volume-based cumulative 10% particle size, a volume-based cumulative 50% particle size, and a volume-based cumulative 90% particle size of this phosphor powder measured by a laser diffraction scattering method are defined as D 10 , D 50 , and D 90 , respectively, (D 90 -D 10 )/D 50 is equal to or more than 0.7 and equal to or less than 1.1.

1 . A phosphor powder which is represented by a general formula M x (Si, Al) 2 (N, O) 3±y  (where M is Li and one or more alkaline earth metal elements and 0.52≤x≤0.9 and 0.06≤y≤0.36 are satisfied) and in which a part of M is substituted with a Ce element,
 wherein the phosphor powder includes phosphor particles in which a Si/Al atomic ratio is equal to or more than 1.5 and equal to or less than 6, 
 an O/N atomic ratio is equal to or more than 0 and equal to or less than 0.1, 
 5 to 50 mol % of M is Li, and 
 0.5 to 10 mol % of M is Ce, and 
 in a case where a volume-based cumulative 10% particle size, a volume-based cumulative 50% particle size, and a volume-based cumulative 90% particle size of the phosphor powder measured by a laser diffraction scattering method are defined as D 10 , D 50 , and D 90 , respectively, (D 90 −D 10 )/D 50  is equal to or more than 0.7 and equal to or less than 1.1. 
 
     
     
         2 . The phosphor powder according to  claim 1 ,
 wherein D 10  is equal to or more than 5 μm and equal to or less than 12 μm.   
     
     
         3 . The phosphor powder according to  claim 1 ,
 wherein D 90  is equal to or more than 18 μm and equal to or less than 38 μm.   
     
     
         4 . The phosphor powder according to  claim 1 ,
 wherein D 50  is equal to or more than 8 μm and equal to or less than 25 μm.   
     
     
         5 . A light-emitting device comprising:
 the phosphor powder according to  claim 1 ; and   a light emitting source.   
     
     
         6 . The light-emitting device according to  claim 5 ,
 wherein the light emitting source emits ultraviolet light or visible light.   
     
     
         7 . An image display device comprising:
 the light-emitting device according to  claim 5 .   
     
     
         8 . An illumination device comprising:
 the light-emitting device according to  claim 5 .